package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

@Component
public class RedisIdWorker {
    private static  final long BEGIN_TIMESTAMP = 1640995200L; // 上海时区2022-01-01 08:00:00
    private static final int COUNT_BITS = 32;

    private StringRedisTemplate stringRedisTemplate;

    public RedisIdWorker(StringRedisTemplate stringRedisTemplate) {
        this.stringRedisTemplate = stringRedisTemplate;
    }

    // 获取全局id
    public long nextId(String keyPrefix){
        // 1、获取时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timeStamp = nowSecond - BEGIN_TIMESTAMP;
        // 2、获取自增序列号
        // 2.1、获取当天日期，通过：分隔，在redis中存自动分层也好做统计
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        // 2.2 添加前缀自增
        long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);
        // 拼接
        return timeStamp << COUNT_BITS | count;
    }
}
